// 贴纸库页面 — 贴纸包浏览 + 分类 Tab

import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:nuanji_app/core/theme/app_colors.dart';
import 'package:nuanji_app/core/theme/app_radius.dart';
import 'package:nuanji_app/data/remote/api_client.dart';
import '../../../widgets/empty_state_widget.dart';
import '../../../widgets/error_state_widget.dart';
import '../bloc/sticker_bloc.dart';

/// 贴纸库页面 — 分类浏览贴纸包
class StickerLibraryPage extends StatefulWidget {
  const StickerLibraryPage({super.key});

  @override
  State<StickerLibraryPage> createState() => _StickerLibraryPageState();
}

class _StickerLibraryPageState extends State<StickerLibraryPage> {
  late final StickerBloc _bloc;
  final _searchController = TextEditingController();

  /// 默认分类 — 从 API 数据动态补充
  static const _defaultCategories = ['推荐', '可爱', '植物', '手绘', '校园', '节日', '文字', '和纸胶带'];

  List<String> get _categories {
    final apiCategories = _bloc.state.packs
        .map((p) => p.category)
        .whereType<String>()
        .toSet()
        .toList();
    if (apiCategories.isEmpty) return _defaultCategories;
    // 合并：推荐 + API 返回的分类
    return ['推荐', ...apiCategories];
  }

  @override
  void initState() {
    super.initState();
    _bloc = StickerBloc(api: context.read<ApiClient>());
    _bloc.load();
  }

  @override
  void dispose() {
    _bloc.dispose();
    _searchController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final colorScheme = theme.colorScheme;

    return Scaffold(
      body: SafeArea(
        child: ListenableBuilder(
          listenable: _bloc,
          builder: (context, _) {
            final state = _bloc.state;

            if (state.isLoading) {
              return const Center(child: CircularProgressIndicator());
            }

            if (state.errorMessage != null) {
              return ErrorStateWidget(
                message: state.errorMessage ?? '加载失败',
                onRetry: _bloc.load,
                icon: Icons.error_outline,
              );
            }

            return Column(
              children: [
                // ---- 自定义顶栏 ----
                Padding(
                  padding: const EdgeInsets.fromLTRB(8, 8, 16, 0),
                  child: Row(
                    children: [
                      IconButton(
                        icon: const Icon(Icons.arrow_back_ios_new, size: 20),
                        onPressed: () => Navigator.of(context).pop(),
                      ),
                      Text('贴纸素材', style: theme.textTheme.titleLarge?.copyWith(
                        fontWeight: FontWeight.w700,
                      )),
                    ],
                  ),
                ),
                const SizedBox(height: 8),

                // ---- 搜索框 ----
                Padding(
                  padding: const EdgeInsets.symmetric(horizontal: 16),
                  child: TextField(
                    controller: _searchController,
                    decoration: InputDecoration(
                      hintText: '搜索贴纸...',
                      prefixIcon: const Icon(Icons.search, size: 20),
                      filled: true,
                      fillColor: colorScheme.surface,
                      border: OutlineInputBorder(
                        borderRadius: AppRadius.pillBorder,
                        borderSide: BorderSide.none,
                      ),
                      contentPadding: const EdgeInsets.symmetric(vertical: 10, horizontal: 16),
                      isDense: true,
                    ),
                    style: theme.textTheme.bodyMedium,
                    onChanged: (v) {
                      _bloc.search(v);
                    },
                  ),
                ),
                const SizedBox(height: 12),

                // ---- 分类选择器（设计规格 8 分类） ----
                SizedBox(
                  height: 40,
                  child: ListView(
                    scrollDirection: Axis.horizontal,
                    padding: const EdgeInsets.symmetric(horizontal: 16),
                    children: _categories.map((cat) {
                      final isSelected = cat == state.selectedCategory ||
                          (cat == '推荐' && state.selectedCategory == '全部');
                      return Padding(
                        padding: const EdgeInsets.only(right: 8),
                        child: FilterChip(
                          selected: isSelected,
                          label: Text(cat),
                          onSelected: (_) {
                            if (cat == '推荐') {
                              _bloc.selectCategory('全部');
                            } else {
                              _bloc.selectCategory(cat);
                            }
                          },
                          selectedColor: AppColors.accent.withValues(alpha: 0.15),
                          checkmarkColor: AppColors.accent,
                          labelStyle: TextStyle(
                            color: isSelected ? AppColors.accent : colorScheme.onSurface,
                            fontWeight: isSelected ? FontWeight.w600 : FontWeight.normal,
                          ),
                        ),
                      );
                    }).toList(),
                  ),
                ),
                const SizedBox(height: 12),

                // ---- 精选贴纸包卡片（动态数据） ----
                if (state.selectedCategory == '全部' && state.filteredPacks.isNotEmpty)
                  Padding(
                    padding: const EdgeInsets.symmetric(horizontal: 16),
                    child: _FeaturedPackCard(pack: state.filteredPacks.first),
                  ),
                if (state.selectedCategory == '全部' && state.filteredPacks.isNotEmpty)
                  const SizedBox(height: 16),

                // ---- 贴纸包网格 ----
                Expanded(
                  child: state.filteredPacks.isEmpty
                      ? const EmptyStateWidget(
                          icon: Icons.sticky_note_2_outlined,
                          title: '暂无贴纸包',
                        )
                      : GridView.builder(
                          padding: const EdgeInsets.all(16),
                          gridDelegate:
                              const SliverGridDelegateWithFixedCrossAxisCount(
                            crossAxisCount: 2,
                            mainAxisSpacing: 12,
                            crossAxisSpacing: 12,
                            childAspectRatio: 0.85,
                          ),
                          itemCount: state.filteredPacks.length,
                          itemBuilder: (context, index) {
                            return _StickerPackCard(
                              pack: state.filteredPacks[index],
                              colorScheme: colorScheme,
                            );
                          },
                        ),
                ),
              ],
            );
          },
        ),
      ),
    );
  }
}

/// 精选贴纸包卡片 — 渐变背景 + 动态数据
class _FeaturedPackCard extends StatelessWidget {
  const _FeaturedPackCard({required this.pack});
  final StickerPack pack;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return GestureDetector(
      onTap: () {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('打开精选贴纸包: ${pack.name}')),
        );
      },
      child: Container(
        width: double.infinity,
        padding: const EdgeInsets.all(20),
        decoration: BoxDecoration(
          gradient: LinearGradient(
            begin: Alignment.topLeft,
            end: Alignment.bottomRight,
            colors: [AppColors.accent, AppColors.tertiary],
          ),
          borderRadius: AppRadius.lgBorder,
        ),
        child: Row(
          children: [
            Container(
              width: 64,
              height: 64,
              decoration: BoxDecoration(
                color: Colors.white.withValues(alpha: 0.2),
                borderRadius: AppRadius.mdBorder,
              ),
              alignment: Alignment.center,
              child: Text(pack.displayCover, style: const TextStyle(fontSize: 36)),
            ),
            const SizedBox(width: 16),
            Expanded(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(pack.name, style: theme.textTheme.titleMedium?.copyWith(
                    fontWeight: FontWeight.w700, color: Colors.white,
                  )),
                  const SizedBox(height: 4),
                  Text(
                    pack.description ?? '${pack.stickerCount} 张精选贴纸',
                    style: theme.textTheme.bodySmall?.copyWith(
                      color: Colors.white.withValues(alpha: 0.85),
                    ),
                    maxLines: 1,
                    overflow: TextOverflow.ellipsis,
                  ),
                  const SizedBox(height: 8),
                  Container(
                    padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 3),
                    decoration: BoxDecoration(
                      color: pack.isFree ? AppColors.secondary : AppColors.rose,
                      borderRadius: AppRadius.pillBorder,
                    ),
                    child: Text(
                      pack.isFree ? '免费' : '精品',
                      style: const TextStyle(
                        fontSize: 11, fontWeight: FontWeight.w600, color: Colors.white,
                      ),
                    ),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }
}

/// 贴纸包卡片
class _StickerPackCard extends StatelessWidget {
  const _StickerPackCard({
    required this.pack,
    required this.colorScheme,
  });

  final StickerPack pack;
  final ColorScheme colorScheme;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);

    return Card(
      elevation: 0,
      shape: RoundedRectangleBorder(
        borderRadius: AppRadius.mdBorder,
        side: BorderSide(color: colorScheme.outlineVariant),
      ),
      child: InkWell(
        onTap: () {
          ScaffoldMessenger.of(context).showSnackBar(
            SnackBar(content: Text('打开贴纸包: ${pack.name}')),
          );
        },
        borderRadius: AppRadius.mdBorder,
        child: Padding(
          padding: const EdgeInsets.all(16),
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              // 贴纸包封面图标
              Container(
                width: 64,
                height: 64,
                decoration: BoxDecoration(
                  color: colorScheme.primaryContainer.withValues(alpha: 0.3),
                  borderRadius: AppRadius.mdBorder,
                ),
                alignment: Alignment.center,
                child: Text(
                  pack.coverImageUrl != null ? '🎨' : pack.displayCover,
                  style: const TextStyle(fontSize: 32),
                ),
              ),
              const SizedBox(height: 12),
              // 名称
              Text(
                pack.name,
                style: theme.textTheme.titleSmall?.copyWith(
                  fontWeight: FontWeight.w600,
                ),
                maxLines: 1,
                overflow: TextOverflow.ellipsis,
              ),
              const SizedBox(height: 4),
              // 数量和价格标签
              Row(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  Text(
                    '${pack.stickerCount} 张',
                    style: theme.textTheme.bodySmall?.copyWith(
                      color: colorScheme.onSurface.withValues(alpha: 0.5),
                    ),
                  ),
                  if (!pack.isFree) ...[
                    const SizedBox(width: 8),
                    Container(
                      padding: const EdgeInsets.symmetric(
                          horizontal: 6, vertical: 2),
                      decoration: BoxDecoration(
                        color: AppColors.accent.withValues(alpha: 0.15),
                        borderRadius: BorderRadius.circular(6),
                      ),
                      child: Text(
                        '积分',
                        style: theme.textTheme.labelSmall?.copyWith(
                          color: AppColors.accent,
                        ),
                      ),
                    ),
                  ],
                ],
              ),
            ],
          ),
        ),
      ),
    );
  }
}